Japanese Laid-open Patent Publication No. 2005-133638 discloses an engine generator in which an engine and a generator are accommodated in a noise-reducing (muffling) case.
The engine generator is provided with a skeletal section of the case formed by a reinforced frame having an inverted U-shape in cross-section erectly disposed on the two side sections of the bottom plate for supporting the engine and the generator. The skeletal section is covered by a resin case. The engine and the generator are accommodated inside the case and a grip for transporting the case is integrally provided to form a small engine generator.
The small engine-driven generator has lower end sections of a pair of reinforcement frames having an inverted U-shape in cross section that are connected only by a bottom plate, and has upper end sections of a pair of reinforcement frames that are not connected by a reinforcement member. Accordingly, the upper end sections of the pair of reinforcement frames are supported by the resin case. Since the engine generator is small, the upper end sections of the pair of reinforcement frames can be supported by the resin case.
However, since the weight is increased when the engine generator is relatively large, it is difficult to use the resin case to support the upper end sections of the pair of reinforcement frames that are an inverted U-shape in cross section. As a countermeasure, it is possible to consider a method in which the rigidity is improved by replacing the resin case with a steel case. However, the weight of the engine generator is increased and the transportability of the engine generator is compromised when the resin case is replaced with a steel case.